Reddit reviews The Body Language of Horses: Revealing the Nature of Equine Needs, Wishes and Emotions and How Horses Communicate Them - For Owners, Breeders, ... All Other Horse Lovers Including Handicappers

Modern Pace Handicapping by Tom Brohammer was a good book to learn pace.

Andy Beyer's Speed Figure handicapping books are still relevant.

Here's a bunch of articles to read: http://www.icapper.com/ - Joe Takach's stuff on how to look at horses is useful. See if you can find some of his videos, they are pretty good.

Bonnie Ledbetter and Tom Ainslee wrote a book on Horse's Body Language - I've found that to be useful.

Six years. That was how long it took to take my Arabian gelding from vicious with a side of 'you ought to put that horse down' to nobody could believe he had ever been anything but amazing. My mother did rehabilitation and told me it was unfair to expect him to be anything but a horse in a field. Someone else told me to euthanize because she couldn't ever expect to handle him and certainly never ride him (like I'd have let that moron touch my breyer model horses, nevermind him). I once told a vet determined to beat him for 'lack of discipline' that I'd make him eat the whip and sue him for every penny in his bank (and was the girl who couldn't say a definitive no on my own behalf). The moral of this story is that your daughter is amazing and from one owner of a 'hopeless' case to another, you have all my undying respect. Given a patient, loving handler and enough time, these amazing animals can turn anything around. Tell your daughter to keep going, one day she may not even remember the day the farrier refused to enter the stall. If she hasn't already, try this book. It was one of my main go to guides through a lot of episodes because it is all about communication on their terms.

https://www.amazon.com/Body-Language-Horses-Communicate-Handicappers/dp/0688036201